POL IJ N ATI NG K M A HC I JL AT El) FLOWERS. 



25 



111 order to (leteriuine the eli'eet of any particular kind of pollen it is 

 necessary to select a flower whose pistil has not yet been exposed, and 

 emasculate it. After emasculation the flower is covered with a bag to 

 keep out all other pollen. Whatever kind of pollen is then applied to 

 the Hower has an op])ortunity to show its effect alone. In the present 

 work generally two to four flowers in each cluster, which looked as if 

 they were just ready to open, but whose stigmas were still closely cov- 

 ered, were selected. All the other flowers of the cluster were first 

 removed. In these ])ollinati()ns pollen from the following sources was 

 used : (1) From the same flower, (2) from a different cluster on the same 

 branch, (.')) from another tree of the same horticultural variety, (4) from 

 another tree of a different variety. 



For pollinating the flowers it was found most convenient to remove 

 a freshly opened anther Avith its i)ollen still adhering l)y pulling the 

 whole stamen out with a pair of fine forceps. The anther, with its mass 



of iiollen, was touched directly to the stigma. The roughened surface of 

 this readily retains a quantity of i^ollen, so that it is perceptibly 

 yellow, and even if it is not completely covered with pollen an exam- 

 ination with a lens will show many pollen grains among the papilhe. 



In some of the early work the flower was emasculated one day and 

 ])ollinated the next, but afterward, as the pollen seemed to adhere 

 l)eiiect]y to the pistil of a freshly emasculated flower, it was applied 

 at once and the liower then covered with a x^iU^^r bag. Subse- 

 quent results showed that there was no disadvantage in the latter 

 method. Generally several flowers were under each bag. When not 

 in use the instruments were kept in a wide-mouthed bottle of alcohol, 

 in order to kill any iiollen adhering to them. They were removed and 

 wiped off before api)lying tlu^ pollen to the flowers in each bag. In 

 t 'lis way all possil)ility of accidental transfer of pollen l)y means of the 

 instruments was avoided. The only chance for infection of the stigma 

 was during the short time (rai ely more than ten minutes) that it took 

 to i)repaie the liowers to V)e covered l)y one bag. Occasionally an 



Fi(i. 2.— Flower of tlie Bai tlott 

 pear (natural size). 



Fig. 3.— P.nd of tbe Earllott 

 ])('a)' witli its ])etals ivnioved, 

 showiiiji, tlie iiirnrvcd sta- 

 iDciis (natural size). 



Fig. 4.— All eniasenlated l)nd 

 of the Bartlctt i»eai-. show- 

 ing' only the five i»istils 

 (natural size). 







